- Category: Non-fiction
- Rating: 4 out of 5
- Tags: Health, Longevity
- How I learned about it: Episode of CBC Radio’s White Coat, Black Art with Dr. Brian Goldman
I heard about this book on an episode of White Coat, Black Art with Dr. Brian Goldman, where it was highly recommended. The recommendation is supported by a glance at the endorsements on the book jacket, with praise from four Nobel laureates and other highly-ranked researchers and authors. This is a serious book based on a hard-nosed look at the latest research into human longevity.
Topol covers much of the same ground as other books on longevity, with a focus on what we can do now to extend lifespan and health span, starting with lifestyle risk factors.
Avoiding risk factors like smoking, high alcohol consumption, obesity, poor diet, loneliness and inadequate exercise can add around seven to ten years to our lives (or even, in one study, over twenty years). Groups with healthy vs unhealthy lifestyles both spend around eight years at the end of their lives with a diagnosis of a major disease like cancer, cardiovascular disease, or type 2 diabetes, but notably, it’s the healthy years that are extended by lifestyle factors, so you’re not just living longer while sick.
One surprise for me was the U-shaped curves of health benefits vs amount of sleep and exercise. Exercise, including strength training, has wonderful benefits. At first, your health risk goes down with more exercise, but at the highest levels the risk starts going back up. The same is true of sleep. The risk of dementia goes down with increasing hours of sleep, up to just over seven hours. After that, the risk of dementia goes up again.
Obesity is a major health problem affecting around a billion people worldwide. Body Mass Index (BMI), is a widely used but inaccurate way to assess obesity, because about one in three people with a normal BMI is obese when body fat is measured. A DEXA scan (dual-energy X-ray absorptiometry) is an accessible, accurate way to measure body fat, muscle mass, and bone density, and can be used to track progress in weight loss and strength training.
Apart from lifestyle factors, there are some new treatments and diagnostic tools making a difference.
For controlling diabetes and obesity, the GLP-1 class of drugs that includes Ozempic and Wegovy is life-changing. They seem to have other beneficial effects, too, on inflammation, heart disease, kidney function, Parkinson’s, Alzheimer’s, and cancer. There are serious drawbacks, however: side effects include nausea, diarrhea, and muscle loss; lifetime use is required; and until pills are developed, they require weekly injections.
Fast, cheap DNA sequencing allows us to create an individualized “polygenic risk score” based on hundreds of genome variants. People identified as being at higher risk can then have early screening and treatment, reducing the impact of disease before symptoms appear.
While not widely used yet, there is more that could be done now to identify early risk factors for heart disease. Testing for inflammation markers in the blood, AI analysis of retina scans, smart watches that accurately track heart rhythms, analysis of the gut microbiome, and heart aging estimates (via plasma proteins assessed for aging of specific organs, which age at different rates) could all improve outcomes for heart disease.
The rise of AI has numerous health benefits. AI retina scans can screen for neurodegeneration; AI speech analysis can predict Alzheimer’s disease; multi-modal AI analysis of one’s whole medical history can aid diagnosis; AI assisted mammogram analysis is better at detecting breast cancer; and AI has helped discover new antibiotics.
Then there are some ideas that haven’t worked out. Dietary supplements are unproven as a way to improve health span. Extreme caloric restriction works in rodents, yeast and fruit flies, but has mixed results in non-human primates (however, consistent with the benefits of lifestyle factors, mild caloric restriction of 12-14% significantly reduces biological age in humans). Measuring telomere length or your epigenetic clock’s biological age is useful for research, but not for individuals. Transfusion of young blood has no proven benefits in humans, and comes with risks.
New treatments are on the horizon, but require more research and clinical trials before becoming available. CRISPR gene editing has potentially revolutionary promise in treating many diseases, but so far is limited and prohibitively expensive. Epigenetic editing also has promise – it was used to treat Creutzfeldt-Jacob disease with programmable methylation, preventing expression of prion proteins. Partial epigenetic reprogramming could remove the epigenetic signatures of aging. There may one day be vaccines for cancer and MS. The drugs rapamycin and metformin show anti-aging effects, and taurine supplements may help. Bacteriophages could be used to treat diseases not amenable to treatment by antibiotics.
In Topol’s view, before we have any general anti-aging treatments, it’s more likely we’ll develop organ-specific treatments that will extend lifespan. Perhaps body-wide aging treatments will follow.
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